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The coconut crab (Birgus latro), the coolest, most awesome, most beautiful inhabitant of the Vamizi Island. These animals have adapted to live around humans and the conservation group on the island does a good job of protecting them.

In July 1937 Amelia Earhart’s plane vanished somewhere over the southern Pacific in the general vicinity of New Guinea. Neither the plane nor her and her co-pilot’s bodies were found during the massive search operation that followed. But two years after her disappearance scattered skeletal remains, later identified as those of a tall woman of European descent, were found on the (then) desert island of Nikumaroro, one of the possible crash sites of Earhart’ aircraft. The skeleton was far from complete and many bones were missing, and the suspicion immediately fell on coconut crabs, common on the island. They were accused of carrying the bones and squirreling them away. But recently a group of history buffs called TIGHAR came to the crustaceans’ defense, claiming that these animals did not customarily carry away food into their burrows. They even conducted an experiment by placing a pig carcass on the beach of Nikumaroro and recorded a fascinating time lapse video of the crabs stripping it of its flesh. Crucially, though, no bones were carried away by the coconut crabs. But it still showed very convincingly that, had the crabs found Amelia Earhart’s body, they would have eaten her completely in a matter of days. I certainly find this explanation far more compelling and easier to think about than the alternative proposed by the authors of the pig experiment – that her body was eaten not by the crabs but by her starving co-pilot who might have survived the crash. Why the hell would he ever resort to cannibalism on an island full of large, delicious crustaceans and coconuts? (And what happened to him? Two years after the crash people arrived on the island and, if movies are any indication, they should have found a muscular demigod who had a meaningful relationship with a volleyball.)

Coconut crabs prefer to be active at night and during the dusk. That is when they emerge from their burrows to look for food.

These thoughts ran through my head as I squeezed it into holes in the rugged karst rocks of Vamizi, an island off the coast of northern Mozambique, looking for coconut crabs. Their burrows turned out to be full of coconut shells and other food remains, indicating that a single experiment good science makes not. I had been dreaming of visiting Vamizi ever since my friend Harith showed me a cell phone photo of himself on the island, holding two coconut crabs. All my life I had been fascinated with those magnificent creatures, the largest, heaviest, most awesome of invertebrates that grace the terrestrial surface of the planet. Some years ago I was lucky enough to see these animals alive, first on Guadalcanal, later on Japan’s Okinawa Island, but in both cases they were individuals already captured by somebody else. In those places coconut crabs are on the brink of disappearance due to habitat loss and overharvesting, and I never had a chance to observe them in their natural habitat. Vamizi, however, a tiny speck of paradise in the Quirimbas Archipelago, still appears to have a healthy population of these animals.

Coconut crabs come in two main color forms, a blue and a red one, both of which can be found in the same population.

Coconut crabs survive on Vamizi thanks to a clever campaign developed by the good people of the Vamizi Marine Conservation Research Centre. If, they say to the locals who traditionally used to hunt the crabs, you kill one, a terrible spell will never let you leave the island. In a country that is full of many ridiculous colorful myths, this scary thought has apparently kept many from falling to the temptation of the coconut crab’s meat. How many crabs survive on the island is unknown but apparently during the wet season it is possible to see a dozen or more coconut crabs on a single stroll through the coastal woodland.

I arrived on Vamizi in June, during the cool, dry season, and the locals were not too optimistic about my chances of finding one. (“They sleep now.”) But I didn’t fly to northern Mozambique on the thieving (camera gear was stolen from our checked-in luggage) and occasionally suicidal LAM airlines (go ahead, google it) to leave without seeing a coconut crab. According to Harith the best chance of finding one would be at a place that reliably provides the crabs with their favorite food. No, not coconuts. They prefer something else – fresh garbage.

“Take me to the dump”, I asked Harith as soon as it started getting dark. As we approached the island’s refuse disposal site we heard a sound that I would have never associated with coconut crabs – loud clicking of empty bottles. And there they were. Two giant, surprisingly colorful animals, moving among a big pile of glass, looking for edible bits of organic matter. The setting was not natural, it certainly wasn’t beautiful, but I almost choked up when I saw them. It was at the same time a fulfillment of a life-long dream, to see coconut crabs in the wild, and a sad, disappointing realization that “wild” is a big pile of junk and rubbish, reeking of rotten food and overrun by rats. The Anthropocene, in its full splendor and glory.

The Anthropocene – is this what a “wild” habitat should be?

Over the next few days my outlook had improved as I counted and photographed the crabs, looking for an indication that the population was breeding on the island. A large part of the island is a well-protected nature reserve, full of gorgeous tropical life, including thousands of land crustaceans, small mammals, breathtaking birds, and cool reptiles (including two species new to science, which Harith will soon be describing.) And I won’t even mention the marine life, which puts Vamizi at the top of the list of the most spectacular diving sites of the world. The most reliable proof of the crabs breeding there would have been finding juveniles still in their shells. Coconut crabs (Birgus latro) are oversized, fully terrestrial hermit crabs, that, just like other members of the hermit crab family Coenobitidae, develop as microscopic planktonic larvae in the ocean, and must don an empty snail shell during the first months of their life on land to protect the still soft and fragile abdomen. Only after reaching the size of about 10 mm do they abandon the shell and assume the symmetrical appearance that differentiates them from other hermits (in all other species the abdomen remains asymmetrically twisted throughout their life.)

Coconut crabs are excellent climbers. Also known as robber crabs, they are known to raid bird nests.

I must have picked up and examined about a thousand hermit crabs but, alas, they all turned out to be one of the two local species of Coenobita. A trip to a coconut grove at the opposite end of the island to look for juveniles hiding in the fallen fronds and coconut husks underneath the palm trees was similarly fruitless. That was worrisome. Rats are known to kill juvenile coconut crabs and the island was full of them. We saw rats not only around the houses but also in the most remote, virtually unspoiled natural habitats of Vamizi. One night my friend Max was startled by a gecko that hurled itself towards his head from the very top of a tall tree to escape a rat chasing it on the thin branches. Adult coconut crabs can and will kill a rat, but younger ones don’t stand a chance. Thankfully, the tourism company &Beyond, which operates the phenomenal eco-resort on the island, has been working diligently to improve the situation. To remove invasive species from Vamizi without harming its native populations of samango monkeys and other small mammals they use specially designed rat-only traps, ultrasonic repellents, and other tools to get rid of the nasty aliens.

Every night I spent hours looking for juvenile crabs along the paths in the forest but all I was seeing were very mature adults. On the last night, dispirited by not finding any proof of new blood in the population, I walked further than usual and ended up being out in the field well past 2 AM. Tired and despondent, I decided to have one last tour of the resort staff houses, the most reliable spot for finding coconut crabs at that time of year. There were a few adults milling around but they soon left for their burrows in the forest. That was it. During my four days on the island I did not see any evidence that the animals were breeding. A similar pattern has been seen in other places inhabited by coconut crabs, where the pressure from invasive species, overharvesting, and habitat loss either prevents the animals from breeding or leads to unnaturally high mortality of juveniles. Despite coconut crabs’ longevity (they can live to be 60), with no young crabs surviving the population eventually dies out.

All I can say is that I am glad that I am taller than a coconut crab (albeit not by much!)

I swept the light of my headlamp around, noticing for the first time the fence at the far end of the compound, overgrown with tall, spiky weeds. It occurred to me that I had never checked what lived among them. If I were a young coconut crab, would I want to compete with the adults, and risk being eaten, by feeding at the same spot, at the same time of night? I climbed the fence and crawled through the thicket, long, thorny branches ripping my shirt and cutting my skin. The ground below the weeds was covered with Coenobita hermit crabs, frantically gorging on discarded scraps of food. And there, among the hermits, were the juvenile coconut crabs. They weren’t much bigger than the large hermit crabs C. brevimanus common on the island, about 5-7 cm long. I let out a sigh of relief. The presence of young coconut crabs made it clear that the population was thriving, or at least not dying out. And the help they get from the conservation group working on the island will certainly improve their chances.

The next morning Harith, Max, and I left the island, having learned not only that it had a good population of coconut crabs, but also that eating oysters directly off the sun baked rocks exposed by the low tide really helps you purge your digestive system. I hope to go back to Vamizi sometime soon and do a more thorough assessment of the crabs’ population. And if I ever perish somewhere near to where these gorgeous animals live, I hope that they find me.

The underside of a blue coconut crab.

The edge of the underside of a coconut crab’s thorax looks very reptilian.

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A silhouette of the first ghost mantis (Phyllocrania paradoxa) recorded from Gorongosa National Park in Mozambique.

I have been working in Africa for quite a while and during this time I have seen my share of iconic animals that epitomize the awesome continent’s fauna. There are still, of course, many that I yet need to meet in person – aardvark, “hairy” Trichobatrachus frog, Acridoxena katydid, to name a few – but luck or stubbornness allowed me to witness others. Few things can match the elation of meeting the gaze of a foraging chimpanzee, discovering a toy-like primate poto in the forest canopy over my head, or running into a fight between a hyena and a leopard over a freshly killed kudu. But my first encounter with one of the less known species, the ghost mantis (Phyllocrania paradoxa), was at least as memorable.

A female ghost mantis (Phyllocrania paradoxa) – these insects are such superb mimimcs of dry vegetation that it is often difficult to tell which part belongs to the plant and which to the insect.

It happened during my first trip to Zimbabwe, at the time when the tumor in Robert Mugabe’s brain was still semi-dormant and the country, “Africa’s bread basket”, was experiencing its first and only period of relative political freedom and economic prosperity. I was staying with a group of friends in the suburbs of the recently re-christened capital Harare, vaguely intrigued with, but blissfully ignorant of why so many houses were standing empty, their gauged windows bordered with the mascara of freshly extinguished flames. Africa was new to me, and I inhaled its intoxicating atmosphere and devoured the sights of alien landscapes and even more alien fauna. But I came prepared – for years before my first visit I had been voraciously reading all that I could find about insects and other members of Africa’s smaller majority. The ghost mantis was one of my most desired quarries and I started looking for it the moment I landed. Alas, a month on and with no trace of the animal, it was beginning to feel as if I were really hunting a ghost. I had spent countless hours sifting through the leaf litter, scanning bushes and trees, sweeping my net through all kinds of vegetation – nothing.

One day I stood on the platform of a railway station, waiting for a train to take me to Bulawayo. It was late October, the peak of the dry season, and shriveled leaves were falling from trees onto my head in a rare, merciful breeze. One, fairly large and twisted brown leaf landed on my shoulder. I tried to brush it off but it just sat there, trembling in the wind. I flicked it again. It landed lower on my sleeve. And then the leaf started to climb up my arm. I looked, still not believing. Could it be? No, this is just a piece of withered plant. But it was, finally, a ghost mantis.

No two individuals of ghost mantids are alike, which prevents their principal predators, birds and primates, from learning how to tell them apart from real leaves.

That was 25 years ago and it took me this long to run across another one. In fact, I had more run-ins with the notoriously elusive leopards than with this incredible insect. But this year, in April, I was finally able to confirm ghost mantids’ presence in Mozambique’s Gorongosa National Park (something that I have always suspected), when my friend, entomologist Marek Bakowski, found the first individual during our annual biodiversity survey. Since then I have encountered a few more ghost mantids in the park.

A Gorongosa ghost mantis with a freshly laid ootheca.

A molting ghost mantis.

Thanks to their otherworldly appearance ghost mantids have long been the favorite of amateur insect collectors and, since they can be easily bred in captivity, they have recently become very popular in the pet trade. Now all you need to do to see a live ghost mantis is to pay a few bucks online and one will be delivered to your door. But for an animal so widely kept, shockingly little is known about its biology and behavior in its natural habitat. Nobody is even sure how many species of ghost mantids there are. Three species of the genus Phyllocrania have been described, only to be synonymized a few years ago. All three were recognized as separate species based on the differences in the shape of the leaf-like process on the head, which can vary wildly within the same population. Ghost mantids, like many other insects that rely on leaf-like camouflage, display an ungodly degree of polymorphism, and no two specimens are alike. But the species’ distribution, throughout sub-Saharan Africa and Madagascar, hints at the possibility of distinct, genetically isolated lineages.

Like most praying mantids, the ghost mantis is an ambush predator, a truly superb one. But unlike many others, it is not inclined to attack members of its own species, and I know of no case of the female devouring a male during copulation, as it is often the case in some other lineages of these insects. In Gorongosa ghost mantids are found mostly in the understory of miombo and mopane woodland, and the only time I witnessed one feeding, it was chomping on a grasshopper. Females produce strange, caterpillar-like oothecae, and newly hatched nymphs look and behave like black ants; after the first molt they turn into perfect replicas of dried-up chaff. How males and females find each other, however, is a mystery to me. It is likely that females, like in other highly cryptic mantids, produce sex pheromones to attract their mates.

Next on the list of African biodiversity icons to confirm in Gorongosa, the Devil mantis. I know you are there and I will find you.

Ghost mantids are extremely polymorphic in both their coloration and the shape of the strange processes on their heads.

“There is a strange ecto on this vesper”, said Jen, a sentence that only recently would have been difficult for me to comprehend. But now, after a few years of rubbing shoulders with mammalogists in Gorongosa I osmotically absorbed enough jargon to understand that she had noticed an interesting parasitic insect on a bat of the family Vespertilionidae. My ears perked up. Jen skillfully disentangled the screeching animal from the mist net and gently stretched the leg of the bat to reveal a small, fuzzy insect snuggly nestled between its fur and the naked tail membrane. Although the circumstances were unusual, considering that we were in the middle of a montane rainforest in Mozambique, and the insect was sitting on a flying mammal, a neural circuit that develops very early on during every entomologist’s training immediately fired a signal – it’s a bed bug!

To be precise the insect sitting on the bat’s body was a bat bug (Cacodmus villosus), a species common in sub-Saharan Africa and associated mostly with bats of the genus Neoromicia. These insects are indeed close relatives of the infamous human bed bugs (Cimex lectularius and C. hemipterus) and share a nearly identical morphology. Until recently entomologists thought that bat bugs spend all of their time in caves and other bat roosting sites, and only briefly visit their hosts’ bodies to feed when the bats are resting. But recent observations, supported by our find, indicate that members of at least this species of bat bugs live permanently on their host. And this is surprisingly interesting.

Bats of the family Vespertilionidae, such as these Neoromicia nana, are frequent hosts of bat bugs, possibly because of these mammals’ low hematocrit, which makes drinking of their blood easier for parasites.

As it turns out, repeated feeding on the same host and in the same spot on the body can be deadly. Not only because the host is more likely to find and kill the annoying parasite, but also because the immune response from the host gets cumulatively stronger over time and greatly increases the mortality of the blood suckers. A few groups of arthropods have successfully managed to adapt (ticks, ceratopogonid and nycteribiid flies, lice, to name a few) but the initial stage of the transformation from a visiting to resident parasite must surely be difficult. This change also requires a great deal of morphological adaptation to become harder to locate and remove by the host. And the bat bug that we saw, despite being very similar in its overall form to the human bed bug, was already displaying some indication of this transition. Its body was harder and smaller than that of the bed bug, which only visits its human hosts for a few minutes every few days. The animal was also covered with long hair, which probably makes it more difficult to be grasped by a bat grooming itself; similar long setae covering the body are the characteristic of another group of ectoparasites, the bat flies (Nycteribiidae).

All members of the family Cimicidae have a similar morphology, and all are obligate hemophages of mammals and birds.

Bed, bat, and bird bugs, members of the family Cimicidae, are obligate hematophages – they must drink animal blood to live. It does not matter much to them whose blood they are drinking. Bat bugs will happily drink human blood, and bed bugs love to feed on chickens. Blood, regardless of its origin, appears to be uniformly nutritious. The reason these insects specialize on particular hosts has to do with the morphology of the red blood cells (erythrocytes) as their sizes vary among animals. For example, chicken erythrocytes are 11.2 µm in diameter, whereas human ones are only 6-7 µm. Since bat and bed bugs drink blood through a needle-like stylet, its diameter has to match that of the erythrocytes of their host and the viscosity of the blood. If you ever had a really good, thick strawberry frap then you know what I am talking about – the pieces of fruit clog the straw and you end up scooping them out of the cup with your fingers (everybody does it, right?) The point is that human blood is easier to drink than that of birds, which might have been the reason why these insects switched hosts sometime during the early stages of human social evolution, from birds or bats that inhabited the same dwellings (swallows are highly probable original hosts). Blood morphology also explains why some bats have and others do not have bat bugs. Bats of the family Vespertilionidae, like the one we caught in Gorongosa, have really low hematocrit (the percentage of red cells in blood) compared to other bats, which makes their blood “thinner” and easier to drink. Not surprisingly they are the most common hosts of bat bugs.

Bed bug (Cimex lectularius) feeding on this human’s blood.

The recent upsurge in bed bug infestations across the world, caused in all likelihood by the sudden availability of cheap airfare and thus a dramatic increase in mixing up of the human population (damn you, JetBlue!), has put these insects into the spotlight. But bed bugs have always been the darlings of behavioral biologists, primarily because of their unusual reproductive behavior. Bat and bed bugs are practitioners of traumatic insemination – males in these insects don’t bother finding the proper opening in the female’s body, but simply jab their sharp copulatory organ into the side of her abdomen and ejaculate directly into the body cavity. This cannot possibly be pleasant. In fact, females who were inseminated in this way show 20-30% decrease in their lifespan due to injuries, and some die immediately after the mating. For this reason female bed bugs had to evolve separate paragenital structures that channel sperm injected into their body cavity into the true reproductive organs. Unfortunately, male bed bugs are particularly horny creatures that will attack anything that moves, including other males, and mate with it. In most bed bug species such intrasexual rape results in the death of the victim male due to ruptured intestines. So severe is the risk of dying from misplaced mating attempts that in the African bat bug Afrocimex constrictus males have developed paragenital structures similar to those of females, just to protect themselves from other lusty males.

Why such bizarre mating strategy has evolved in bed bugs (and a few other invertebrate groups) is still a mystery. Most explanations center around sperm competition – by injecting sperm directly into the body of the female the males bypass mating plugs that females of many animals develop to stop future matings. It may also give males a chance to send sperm closer to the ovaries, or simply avoid having to perform some ridiculous dance or other display in order to be accepted by the female as a mating partner. There is also a theory that by injecting sperm directly into the gut the male bed bug feeds the female (his sperm is indeed partially digested), a form of a nuptial gift. Thanks, but no thanks!

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Rock scorpion (Hadogenes granulatus) from Bunga Inselberg in Gorongosa, one of the largest scorpions in the world.

One of the more entertaining consequences of posting images of obscure, rarely seen animals on this blog or on my Facebook page is that I am sometimes accused of faking them, especially if a Google search by those who doubted the veracity of my photos did not produce similar pictures taken by other photographers. This happens particularly often with animals that are the largest of their kind, be it a giant land crab or, more recently, a parasitic bat fly. I wonder if the photos in this post will be met with similar incredulity.

Bunga Inselbergs in Gorongosa National Park, Mozambique

Last month I lead (lured) a group of researchers to a remote corner of Gorongosa National Park to continue the documentation of the biological richness of this remarkable place. Our camp was at the foothills of the Bunga inselberg, one of several small, isolated mountains in the western part of the park. These inselbergs have never been biologically explored and although we did not expect to find any endemic species there was always a chance of encountering rare or new to science organisms. These inselbergs are, in an essence, giant piles of volcanic rock, covered with a very thin layer of topsoil and a dense carpet of woody vegetation. Such a habitat is heaven for a lot of animals but, to my great relief, not lions and elephants. This meant that we could roam freely around the inselbergs in a relative safety, not constrained by the need to be always accompanied by armed park rangers. I say “relative” because Africa is rich in things that can get you, and Bunga inselbergs were no different – on my first visit there my friends and I were attacked by a cloud of wild honey bees, and on the following day I pulled nearly 150 stingers from my arms and neck. (It was a close call – I remember thinking “At least this is the end fit for an entomologist,” before losing consciousness.) Thankfully there were no similar incidents during this survey, although I did make sure that every person carried an Epipen kit to treat potential anaphylactic shock.

The median ocelli of the rock scorpion (Hadogenes granulatus) are protected from scratching against rocks by elevated ridges (green arrow). These are absent in species that live in equally constrained but softer environments, such as this Opistacanthus (below) found under tree bark.

Lifting heavy volcanic rocks to look for animals during the survey was hard work, but it was also immensely rewarding. Each flat piece of basalt could have been hiding a cool gecko, a snake, a family of crickets, some awesome beetles, or a scorpion, and it was the last one that gave me the biggest surprise. Rock scorpions of the genus Hadogenes are considered the largest, or at least the longest, scorpions in the world. Some species can reach the length of 22 cm and several individuals from Bunga were at least this big. Granted, a large portion of the body is the long and thin telson (“tail”) of the animal, but it is still a spectacular beast, which will make you pause when you see it scurrying around your fingers. All species of Hadogenes are obligate lithophiles; in other words, they love rocks. Their bodies are perfectly adapted to squeezing into narrow crevices, and their feet carry stiff setae and strongly curved claws that allow them to cling to even the smoothest rocks (and hang from rocks upside down, something that few other scorpions can do). Their median ocelli – the main pair of eyes – are protected by elevated ridges that prevent them from scratching against the rocks, and the entire body is flatter than in any other scorpion of similar size.

Like many scorpions, members of the genus Hadogenes display a beautiful, blue fluorescence if exposed to ultraviolet light. A recent study suggests that this helps these nocturnal animals detect and avoid light.

But, as it is often the case, a large size and a scary appearance do not necessarily translate into true ability to inflict harm. The giveaway is the telson, which in rock scorpions is long and thin, betraying the presence of weak muscles and a small venom gland, and thus the lack of reliance on venom for capturing prey and defense. They can and do sting, of course, but the strength of their venom is no greater than that of a bee (and, thankfully, scorpions do not move in large swarms and are far more friendly than those pissy little bits of flying pain). A few species of Hadogenes have the ability to spray venom towards the attacker, which can cause painful irritation if the droplets get into your eyes, but otherwise they are harmless. In fact, an article (pdf) describing the medical importance of rock scorpions puts more emphasis on their ability to pinch your fingers then to envenomate.

Scorpions of the genus Hadogenes occur in rocky habitats across southern and East Africa, often on isolated mountains, leading to frequent allopatric speciation and a high number of endemic species. When I first found rock scorpions on Bunga I was hoping for a new, undescribed species but, alas, this turned out not to be the case as they were all members of H. granulatus, a species known from other places in Mozambique.

I photographed one of the individuals sitting on a vertical rock next to my hand. I knew that the animal was pretty harmless but I still was not looking forward to comparing its venom to that of a bee, and decided not to shoot it sitting directly on my hand. And, of course, it made it much easier to manipulate the image in Photoshop to make the scorpion appear bigger. (Kidding!)

Rock scorpions’s body is strongly flattened, perfectly adapted to squeezing into the narrowest of crevices.

Flavio Artur, Ricardo Guta, and I, 24 hours after being attacked by a swarm of wild African honey bees. On that morning I pulled out nearly 150 stingers from my skin.

After a long hike in the scorching heat of the African savanna the cool, shady patch of tall miombo forest looked like heaven to us. I was in the southern part of Gorongosa, looking with a few friends for some elusive species of arthropods. But we were having little luck finding any and after several hours of strenuous walking the morale was low. As we stepped under the dark, inviting canopy of the forest, the drop in the temperature was palpable and we all relaxed, slowed down the pace, and the mood in the group immediately improved. But then, suddenly, somebody yelped “Ouch!” and at the same moment I felt a painful pin-prick at the back of my neck. Crap, tsetse flies! We looked around – they were everywhere. Clouds of them. We could see groups of dozens clumping on vegetation, taking into the air the instant they noticed the movement of our bodies. We ran.

A painting (undoubtedly the first and only) of a bat fly (Penicillidia sp.) burrowing in the fur of a Long-winged bat (Miniopterus).

Tsetse flies have long had a reputation for being one of the scourges of Africa, alongside malaria, crocodiles, and the plague of locusts. And deservedly so – some species of tsetses, all members of the genus Glossina, are vectors of nasty protozoans, including Trypanosoma brucei, the cause of the deadly sleeping sickness. Luckily for us, Gorongosa tsetses carry a different Trypanosoma species, T. congolense. This protozoan does not affect humans but unfortunately causes the chronic Nagana disease in cattle and horses, which explains the nearly complete absence of these animals around the park and in almost the entire region of central Mozambique. But knowing that tsetse bites are not going to kill us did not make them any more pleasant. Tsetses are large flies, about the size of a bee, and their skin-piercing mouthparts are much thicker than those of a mosquito. In other words, it hurts like hell when one jabs you with its proboscis, and you flail your arms like a madman to shoo it away while the fly escapes unharmed.

Members of the family Streblidae, such as this Raymondia sp., collected from the Hildebrandt’s horseshoe bat (Rhinolophus hildebrandtii), often exhibit interesting adaptations in their wing morphology, such as the ability to fold them longitudinally along the back. This presumably helps them move swiftly in the pelage of their hosts.

But count yourself lucky. Imagine instead that you cannot shoo them away. You try to smack one but it runs, hides in your hair or some place where you are not able to reach, and it continues to bite. It only leaves your body to give birth somewhere in your house but then immediately runs back, guided by your scent and body heat. Oh, and imagine that this fly is the size of your fist (or a small puppy). Welcome to the world that bats are forced to live in.

Tsetses are members of a large group of flies, the superfamily Hippoboscoidea, all of which are exclusively hematophagous – blood is the only food that they are interested in. The tsetse family (Glossinidae) is the most basal (unsophisticated, one might say) member of this lineage of insects – they are always looking for a blood meal but never evolved the ability to stay with their tasty host. Bats are unlucky to have been colonized by two much savvier families of flies, the Nycteribiidae and Streblidae. These insects know the value of a good host and, once they landed on the furry back of a bat, they never leave it again. Over millions of years of coevolution with their mammalian hosts the bat flies have undergone a remarkable transition. From a free-flying ancestor, most likely very similar to today’s tsetse flies, emerged several lineages of highly modified, often completely wingless, spider-like creatures. Their body became flattened and very hard, making it almost impossible to squash them against the skin. In the family Nyctiberiidae the head turned into a small appendage that can be safely tucked away in a protective groove on the back and all traces of wings completely disappeared. These flies cannot survive for long outside of their host’s body and only feel at home when scurrying at an alarming speed in its dense fur. Their feet are armed with large claws that make it almost impossible to dislodge them from the hair of their host. They really don’t look like flies and when a friend spotted one on the body of a bat she called me to collect the bat’s “pet spider.”

In the closely related family Streblidae the wings may or may not be present, but even in the winged species the body is modified for squeezing through the fur, and members of the subfamily Ascodipterinae go even further in their commitment to the host. Much further. Once a female lands on a bat she sheds her wings and legs (yes, legs) and burrows head-first into the skin. Once there, her head and thorax sink into her own abdomen, and the skin of the bat overgrows her body. She becomes one with her host.

Penicillidia bat flies (Nycteribiidae) are some of the most unusual members of the order Diptera and hardly resemble their winged relatives. This individual was collected from a Long-winged bat (Miniopterus natalensis) in Gorongosa, Mozambique.

Female bat flies, like their relatives tsetse flies, are remarkably good mothers. The great majority of insects relies on what ecologist call “r-selection” in their reproduction – they lay hundreds or thousands of eggs, betting on one or two of them making it to adulthood. Bat flies, on the other hand, rely on “K-selection” – like humans, they prefer to invest a lot in a much smaller number of offspring, hoping that they will all make it to the reproductive age. They are larviparous – instead of laying eggs the female gives birth to a single, fully developed larva, which immediately turns into a pupa. While in her mother’s body, the larva feeds on “milk glands”, analogous to the mammalian mammary glands (if they were located in the uterus), and develops safely protected from the elements and predators. When the time comes for the mother to give birth she walks off the bat’s body and attaches the larva to the wall of the bat’s roosting place, usually a cave (which explains why bats that roost in rolled-up leaves and other less permanent places have fewer ectoparasites). Then she turns back and runs towards her host, guided by the smell and the heat of its body.

The recent Ebola crisis brought back the attention of the medical community to bats as potential reservoirs of the virus. Although there is no evidence that bats are in fact harboring the virus, there seems to be some correlation between instances of the outbreak and the presence of large numbers of bats in the affected areas. While reading the literature on both Ebola and bat flies I found it rather curious that nobody has tested bat flies for the presence of the virus – these are relatively very long lived (195 days on average) insects, who always stay (as pupae) at the roosting sites of bats, even when the hosts leave to forage elsewhere. They often move from one host species to another and, this point makes me really wonder why nobody has seriously looked at these flies as potential vectors, occasionally drop on and bite people. We know that they harbor a slew of pathogens – a recent study conducted in Gorongosa National Park on bats Rhinolophus landeri and Hipposideros caffer showed that flies living on these animals are vectors of Trypanosoma species that are ancestral to those that cause Chagas disease. Add to this the fact that one of the first cases of Marburg disease in Zimbabwe (caused by a virus related to Ebola) was caused by a bite of an arthropod (by default all unidentified bites seem to be classified by the medical community as “spider bites” and spiders in the area were tested, predictably unsuccessfully, for Marburg). It is far more likely that the bite was caused by a fly that fell off a bat.

A friend of mine recently expressed her dismay at “lowly” parasites. I beg to differ – if anything, parasites, including bat flies, are incredible examples of evolution at its best, organisms capable of both adapting to life in the most hostile of environments (the very substrate you live on wants you dead!) and resisting diseases that live inside your body. I cannot promise that I will not try to smack the next tsetse fly that lands on me but at least I promise that I will do it in the most respectful, considerate way.

Louse flies (Hippoboscidae) are closely related to bat flies and equally modified for ectoparasitic lifestyle. This Lipoptena sp. was collected from a Nyala antelope while it was being fitted with a GPS collar. Louse flies are parasites of large mammals and birds, and some are considered serious pests of sheep.

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In my lap was a specter, one of the most elusive animals in sub-Saharan Africa. I’d been waiting years to see it, and now it was weighing abrasively on my thighs like a sack of bricks stuffed into a giant pinecone. It wiggled and unfurled its roly-poly body just enough to reveal an eye like sticky caviar, its tongue whizzing in and out and reinforcing the illusion that this scaly orb was a dragon come to life.

But it was a warm-blooded, placental mammal, confirmed by the tiny body double that was furled in her grasp, suckling at the teats exposed on her underbelly. The mother and her pup were ground pangolins (Smutsia temminckii), one of eight species belonging to the mammalian order Pholidota, found only in Africa and southeast Asia. Though often called scaly anteaters, pangolins are unrelated to the Vermilingua, the suborder containing true anteaters. Actually, pangolins aren’t closely related to much of anything; these animals are unique, clinging to a long, isolated branch on the tree of life.

Safe at last – rescued from poachers, a Ground pangolin and her baby boy are going back to Gorongosa National Park to be released back into their habitat.

We were in Gorongosa National Park, Mozambique, and someone had told us about her. There was a man in a village across the river, the whispers went, selling her for the low price of 22,000 meticais (about $700 USD). Like rhinos, pangolins have fallen victim to a deeply-held misconception that their keratinous scales hold medicinal magic: that they can cure skin disease, reduce swelling, or even conquer cancer. I’ll tell you now: save yourself the money and the risk of jail time, and just chew on your nails – they are chemically and physiologically the same.

One day and a sting operation later, the pangolin was in my lap. Park rangers, working with the local police, arrested the poachers and rescued the animals. We were driving them out into the core of the park, where we’d release them, safely distant from grasping human hands. Though the pinecone plates of a pangolin’s back can and do stand up to being chewed on by lions, these animals are no match for a human that’s interested enough to simply pick one up and carry it off. Their only other defense is their smell, an indescribable odor that originates from a noxious acid secreted from glands below the tail.

I ran my hands along the pangolin’s scales. They were grooved and brittle-chipped, crooked and mud-splattered like fingernails that had seen many years of working with the land. In Asia, the scales of confiscated pangolins bear the circular scars of punches used for medicine. Even the artful hand of evolution, which had crafted this unique armor from a plush pelt, couldn’t save them.

Bipedal and armed with massive claws, a Ground pangolin could easily be confused with a carnivorous Jurassic raptor. But these gentle mammals feed exclusively on termites and ants, and their only defense is a thick armor of keratinous scales.

As she unrolled herself from her fortress, a second head surfaced, tiny and pale. It was her male pup, the only one that will be born until he reaches sexual maturity in two years. He was born in captivity, a side effect of stress, and an unrealized bonus prize for the poacher. His scales were half-baked, pliable, and the dark shriveled stump of an umbilical cord poked from his round belly. He moved in the shivering stutters of an infant still unsure about the world.

As the pup crawled up my arm, the mother thrust out a hooked hand to right herself. Her claws, the length of my fingers, gripped my jacket like rusty nails and tore a gaping hole in the material as they bore into my side. I jumped, and she rolled back into a ball, her pup safely inside. These formidable sickle-claws are used to tear open termite mounds and ant nests, shredding the hard earth in search of scrambling adults and doughy larvae. The pangolin laps them up with its sticky-salivating tongue, longer than its own body and the longest relative to body size of all known mammals. Because pangolins lack teeth entirely, keratinous folds line their stomachs with inverse armor, grinding the insects to bits with the help of ingested pebbles.

Having spent a month in captivity, the pangolin, her baby tenuously clinging to her back, takes the first steps as a free animal.

We finally reached an appropriate site: far from the park’s perilous edges, the forest bulged above a tapestry of termite mounds. We set her gently on the ground, and waited.

Pup clinging to her back, she stood and sniffed the air, taking a few moments to orient herself to her new and safer home before choosing a bearing. Her scales clack-clacking, she ambled away on her hind feet like a drunken Velociraptor, tail out and claws curled against her chest. It’s hard to walk on all fours when you’ve got scythes for hands.

In Chinese mythology, pangolins are wayfarers. It’s said that they travel the world by digging through the core of it, tying the earth together with a vast underground labyrinth. In Cantonese, they’re called chun-shua-cap, “the animal that bores through the mountain.” I’d like to think she’s safely reached the Alps by now.

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Most people would hardly look twice at this small, pink “worm”, but this amphisbaenian (Chirindia swynnertoni) from Gorongosa probably looks like the now extinct ancestor of all snakes.

Having drawn the short straw at the phenotypic lottery I have always felt a special kinship with creatures that most people dismiss as too small, too creepy, too unattractive. Because these are (I tell myself) the hallmarks of the truly interesting organisms, ones that have followed the less-trodden paths of unusual specialization, remarkable adaptations, evolutionary ingenuity.

One such organism, about the existence of which I learned as a young child from an old zoology textbook, was Bipes, an amphisbaenian. It was a chimeric, strange creature, with the appearance of a pink snake, but equipped with a pair of shovel-like legs at the front end of its long body. There was a striking resemblance between that creature and a picture of a dragon that I had seen in the illustrated edition of the Old Testament from my Sunday School (which, incidentally, offered its classes on Monday nights), and I was instantly hooked.

Although it looks soft and squishy, the amphisbaenian’s head hides a strong skull that allows it to push through even the hardest soil.

Amphisbaenians are reptiles, but so unusual that for the longest time they were considered a separate order of these animals. For one, they look nothing like a vertebrate – the last couple of times that somebody brought me an amphisbaenian they were under the impression of having collected an earthworm (unlike Bipes, most species are legless.) Their annulated body is usually pink or covered with irregular, white and dark blotches, a clear indication that these animals don’t care about how they are perceived by others. And for a good reason – why bother with the looks if your entire life is spend underground and you yourself are blind. Better to invest the energy that would have been spent on the irrelevant appearance into things such as a thick skull and powerful thoracic muscles that will allow the animal to push effortlessly though the soil in search of prey.

My assistant Ricardo Guta looking for insects and other animals in the habitat of the Gorongosa amphisbaenian.

Recent phylogenetic studies revealed that amphisbaenians are not a separate, primitive order of reptiles, but rather a highly derived, supremely modified lineage of lacertiform lizards. It is very likely that the next step in this transition to a subterranean lifestyle was the complete loss of limbs and girdles, a dramatic reshaping of the skull, the loss of eyelids and, eventually, the emergence of a brand new group of animals, the snakes. In fact, the most basal (primitive) snakes, the Typhlopidae and other related families, look remarkably like the amphisbaenians.
A few days ago I was in the southern part of Gorongosa, checking out sites for the second biodiversity survey of the park, and there, in a dry, crumbling log, I found a beautiful little amphisbaenian, Chirindia swynnertoni. This species is rarely seen, and thus I promptly followed a recommendation of a field guide to amphibians and reptiles of East Africa: “Anyone finding a worm-lizard [amphisbaenian] should take it to a museum.” I still haven’t had the heart to preserve it for the Gorongosa Synoptic Collection, and instead I have been watching it for days, transfixed by its amazing ability to squeeze into the hardest soil with the body that looks like an overcooked string of pasta, and with a baby-pink face of a newborn. It has been feeding on termites and ant larvae, crushing the insects with its tiny yet powerful jaws. And I find it fascinating (and somewhat rewarding) that from so seemingly unassuming a beginning came a lineage of animals that has terrified the human psyche since the time of Eden.